1. Field
At least one example embodiment relates to electrostatic discharge (ESD) protection devices, and more particularly, to ESD protection devices used for input/output (I/O) terminals of a semiconductor device.
2. Description of the Related Art
At input/output (I/O) terminals of a semiconductor device, an electrostatic discharge (ESD) protection device may be provided for protecting the semiconductor device. A conventional ESD protection device may include a plurality of unit devices for clamping excess voltages at the I/O terminals, which may occupy a large horizontal area. Thus, forming the ESD protection device having a narrow horizontal area is desired.